1. Technical Field
The present invention relates to a liquid-ejecting head and liquid-ejecting apparatus in which liquid is ejected from a nozzle opening, especially relates to an ink jet recording head and ink jet recording apparatus in which ink is ejected as the liquid.
2. Related Art
An ink jet recording head is one of typical examples of a liquid-ejecting head from which a droplet is ejected. Examples of the ink jet recording head include a recording head which includes a channel-forming substrate having a pressure-generating chamber and a piezoelectric actuator provided on one surface of the channel-forming substrate. In such a recording head, the piezoelectric actuator is deformed to apply pressure to the inside of the pressure-generating chamber, thereby ejecting an ink droplet from a nozzle opening.
In such an ink jet recording head, components contained in an ink evaporate from the nozzle opening, thereby increasing the viscosity of the ink. Variation is therefore caused in ink droplet ejection characteristics with the passage of time, and the quality of liquid ejection cannot be accordingly uniformly maintained. In addition, components contained in ink precipitate with the result that difference is generated between components contained in a continuously ejected ink droplet and components contained in an intermittently ejected ink droplet. Variation is therefore also caused in quality of liquid ejection.
An ink jet recording head is therefore proposed (for example, JP-A-2009-247938 and Japanese Patent No. 3161095), in which a plurality of pressure-generating chambers are in communication with a common liquid chamber in common, ink is supplied to the common liquid chamber and is subsequently retrieved from the common liquid chamber, and the supplying and retrieving are repeated with the result that the ink is circulated, thereby suppressing the increase of ink viscosity and precipitation of components contained in the ink.
In order to circulate ink in a common liquid chamber which is in communication with each of the pressure-generating chambers as in the case of JP-A-2009-247938 and Japanese Patent No. 3161095, however, a pressure generator such as a pump needs to be provided. The size of the recording head is therefore problematically increased, and production costs are also disadvantageously increased.
Such disadvantages arise not only in the ink jet recording head from which ink is ejected but in a liquid-ejecting head from which liquids other than the ink are ejected.